The desirability of enhancing optical scenes, aerial photographs, radar and infrared images so as to cue an observer to the presence of targets having specific characteristics has been well recognized. Many of the prior approaches to the spatial filtering of images, with filter bandwidths adjustable by the human observer so that continuous observation can be had of dynamic images with selected spatial bandwidths have appeared theoretically possible, but they have not heretofore been feasible due to their great expense, the voluminous equipment required, and the slowness of operation. The best known prior art is that contained in U.S. Pat. No. 3,283,070 to patentee M. D. Prince and U.S. Pat. No. 3,566,027 to patentee T. O. Paine.